&GAS: ADD


item

  Can be any of the following:

  ----------------------------------------------------------------------
  Item                     Explanation
  ----------------------------------------------------------------------
  ATTACHMENT-COEFFICIENT   Attachment coefficient/pressure, in 1/cm.Torr
  DRIFT-VELOCITY           Drift velocity in cm/microsec
  ION-MOBILITY             Ion mobility, in cm2/microsec.V
  LONGITUDINAL-DIFFUSION   Longitudinal diffusion * sqrt(pressure),
                           cm*sqrt(Torr) for 1 cm of drift
  LORENTZ-ANGLE            Lorentz angle, in degrees
  TOWNSEND-COEFFICIENT     Townsend coefficient/pressure, in 1/cm.Torr
  TRANSVERSE-DIFFUSION     Transverse diffusion * sqrt(pressure),
                           cm*sqrt(Torr) for 1 cm of drift
  ----------------------------------------------------------------------

  Note that the same scalings have to be applied as for the TABLE.

function

  The function may depend on the following variables:

  ----------------------------------------------------------------------
  Variable   Meaning                                Unit
  ----------------------------------------------------------------------
  ATTACHMENT Attachment coefficient / p             1/cm.Torr
  COS_EB     Cosine of angle between E and B        -
  EP         Electric field / p                     V/cm.Torr
  LORENTZ    Lorentz angle                          degrees
  MOBILITY   Ion mobility                           cm2/microsec.V
  SIGMA_L    Longitudinal diffusion * sqrt(p)       cm*sqrt(Torr) per cm
  SIGMA_T    Transverse diffusion * sqrt(p)         cm*sqrt(Torr) per cm
  TOWNSEND   Townsend coefficient / p               1/cm.Torr
  VELOCITY   Electron drift velocity                cm/microsec
  ----------------------------------------------------------------------

  The variable EP can always be used, COS_EB should only be used in
  2-dimensional tables i.e. when Magboltz has prepared the transport
  tables in the presence of a a magnetic field. The transport properties
  should be used only insofar as they have been entered already.

VS

  If you wish to add experimental data to a table, you should prepare
  2 vectors: one that contains the E/p values of the measurements and
  one that contains the quantities measured.

  The E/p vector must cover the entire range of the table - no attempt
  is made to extrapolate the data you provide.

  The E/p values in your measurements do not have to coincide with the
  E/p values present in the table - your measurements will be
  interpolated at the values of the table and these interpolations are
  stored instead of the actual measurements.

ORDER

  Selects the degree of polynomial interpolation in the pair of vectors.

  When the data is smooth, a value of 2 (quadratic interpolation) is a
  good choice. This may however lead to intermediate points with a
  negative value in for instance Townsend coefficient tables that
  usually start at 0. For such tables, linear interpolation is advised.

  Instead of ORDER 1, you may also type LINEAR. QUADRATIC is a synonym
  for ORDER 2, CUBIC for ORDER 3.

Keyword index. Formatted on 10/11/98.